1. Technical Field of the Invention
This invention relates generally to wireless communication devices and more particularly to radio frequency integrated circuits used within such wireless communication devices.
2. Description of Related Art
Communication systems are known to support wireless and wire lined communications between wireless and/or wire lined communication devices. Such communication systems range from national and/or international cellular telephone systems to the Internet to point-to-point in-home wireless networks. Each type of communication system is constructed, and hence operates, in accordance with one or more communication standards. For instance, wireless communication systems may operate in accordance with one or more standards including, but not limited to, IEEE 802.11, Bluetooth, advanced mobile phone services (AMPS), digital AMPS, global system for mobile communications (GSM), code division multiple access (CDMA), local multi-point distribution systems (LMDS), multi-channel-multi-point distribution systems (MMDS), and/or variations thereof.
Depending on the type of wireless communication system, a wireless communication device, such as a cellular telephone, two-way radio, personal digital assistant (PDA), personal computer (PC), laptop computer, home entertainment equipment, et cetera communicates directly or indirectly with other wireless communication devices. For direct communications (also known as point-to-point communications), the participating wireless communication devices tune their receivers and transmitters to the same channel or channels (e.g., one of the plurality of radio frequency (RF) carriers of the wireless communication system) and communicate over that channel(s). For indirect wireless communications, each wireless communication device communicates directly with an associated base station (e.g., for cellular services) and/or an associated access point (e.g., for an in-home or in-building wireless network) via an assigned channel. To complete a communication connection between the wireless communication devices, the associated base stations and/or associated access points communicate with each other directly, via a system controller, via the public switch telephone network, via the Internet, and/or via some other wide area network.
For each wireless communication device to participate in wireless communications, it includes a built-in radio transceiver (i.e., receiver and transmitter) or is coupled to an associated radio transceiver (e.g., a station for in-home and/or in-building wireless communication networks, RF modem, etc.). As is known, the transmitter includes a data modulation stage, one or more intermediate frequency stages, and a power amplifier. The data modulation stage converts raw data into baseband signals in accordance with a particular wireless communication standard. The one or more intermediate frequency stages mix the baseband signals with one or more local oscillations to produce RF signals. The power amplifier amplifies the RF signals prior to transmission via an antenna.
As is also known, the receiver is coupled to the antenna and includes a low noise amplifier, one or more intermediate frequency stages, a filtering stage, and a data recovery stage. The low noise amplifier receives inbound RF signals via the antenna and amplifies then. The one or more intermediate frequency stages mix the amplified RF signals with one or more local oscillations to convert the amplified RF signal into baseband signals or intermediate frequency (IF) signals. The filtering stage filters the baseband signals or the IF signals to attenuate unwanted out of band signals to produce filtered signals. The data recovery stage recovers raw data from the filtered signals in accordance with the particular wireless communication standard.
A critical issue with any mixed signal circuit, including radio transceivers, is minimizing noise, especially at the sensitive points within the mixed signal circuitry. In radio transceivers, one sensitive point is the receiver input that receives radio frequency (RF) signals from an antenna. To minimize noise sensitivity, a receiver input includes a low noise amplifier to receive and subsequently amplify incoming RF signals. Further, most low noise amplifiers are designed to have an input impedance to substantially match the impedance of the antenna at radio frequencies. Alternatively, the receiver may include an impedance matching circuit between the antenna and low noise amplifier to provide the desired impedance matching.
When the RF transceiver is implemented as an integrated circuit, it includes a die mounted within a package. The packages die (i.e., the integrated circuit) is then mounted on a printed circuit board, which includes the antenna. Conventional packaging of the die may be done using commercial packages (e.g., ball grid array (BGA), LPCC, et cetera) where the die is placed in the center of the package. While such packaging has provided adequate performance in the past, as radio frequencies increase and/or the data throughput demands increase, such conventional packaging provides unacceptable levels of parasitic components (e.g., capacitance and/or inductance). Such parasitics increase the noise levels of the radio frequency integrated circuit, degrade the input signal to the radio receiver, degrade output power of the radio transmitter, and thus limit the radio transceiver's overall performance.
Therefore, a need exists for a radio frequency integrated circuit die packaging configuration that minimizes adverse affects of packaging parasitics.